Counterbalancing mechanism for drilling-machines



.W. T, SEARS.. COUNTEBBALANCING MECHANISM FOR DRILLING MACHINES.

APPLICATION FILEI) NAYS. |918.

Patented Feb. 3,1920; I

IIA

Tram/fr v I i llllillllh 'we i i dirigirte WEILLARD SEARS, 0F BROOKLYN, NEVI YURK, ASSIGNOE TO NLES--BEMENTFOW ClVlFl-NY, 0F NEl YGRK, N. Y., A CORPl/ATON 0F NET? CI'ETERBALLNCSNG 'MECHANSM FOR DRLLNG-MACWTWE Specification of Letters Eatent.

Patented L?, lltid.

.application filed May 9, 19H5. Serial No. 233,405

To all wauw t may macero:

lle it known that l, lVILLAno T. SEARS. a citizen ot' the United States., residing; at Brooklyn, in the county of Kings and State of New York, have invented certain new and useful improvements in Counterbalaneing Mechanisms for ilrilling-h/laohines, of which the following is a specification.

The inventien` is particularly applicable to universal radial drilling,l machines in which the spindle is angularly adjustable with ree-peet tothe anni and in which the arm is angularly adjustable with respect the ooluinni but the invention @an also be used 'for a plain radial drilling machine. ylhe invention relates to a eounterbalanoing device ot the -elaes in which the counterL Weight la movable longitudinally parallelly with the Spindle but in the opposite direc tion,`.tlie line of movement of the counterweig'ht being1 adjusted angularly in accord ance with the angular adjustment of the Spindle. the counterweight is connected with the spindle by gearing, this gearing engaging a rack on the counterweight which is so located that .its hcentral oit-ch line passes through, the lcenter of gravity.'

ln the accompanying drawing' l have shown two embodiments of the invention, either oi which may be used as required to moet the conditions of a particular design. lt will bev understood, however, that the drawing is intended to be inerely illustrative and 'that there may be many variations, pan ticularly in the general arrangement and construction of parte. without departing from the Spirit of the invention ae eet forth in the appended claims.

Ot the drawing:

Figure l is a side View of a chine embodying the invention.

Fig. '2 is an end view.

ll lg'. 3 is a fragmentary horizontaleectional view taken alongthe linee 3--3 olf Figs. 2 ande.

Fig. 1lie a fragmentary elevational view fot the parte shown in Fig. 3.

Fig. 5 is a view similar to Fig. 3 out showu ing' another embodiment of the invention.

6 is a fragmentary sectional view taken alone' the line 6--6 of Fig. 5.

Referringto the drawing, l represents the main eoluinn of the machine, this column being mounted on a base 2 so as'to be capable drilling` maln accordance with 'the invention,

adjustable with respect to the inenibe 3 f about the axis of the shaft 5. Secured the nieinber 3 at the side opposite the arno` ie a caeinp; o and a niotor 7. Suitable gearing' ie priwided in the casing' l5 for driving; the ann shaft 5.

Carried by the aiin and preferably longitudinally movable therealong is eaddl e Secured vthe saddle a head 9 whit,... is angularly adjustable about a horizontal axis perpendicular to the axis ofthe shaft 5. Mounted inthe head 9 is a spindle l0 which is normally vertical7 ae shown in the drawing, but which is angularly adjustable with the head. The drill is secured `to this spindle in any usual or preferred way.v The spindle l is longitudinally movable to bring' the drill into operative position or to eieot feeding. The spindle is rotated from the shaft in the usual way by ineane of bevel'gearing ,11, the initial drivingA element of this gearing being1 splined on the shaft 5 and the .final driven element thereoll being; eplined on the spindle 10. `Tlris ge eine; permite the saddle to be moved longitudinally of the arrn, or the spindle to be moved longitudinally of the head, oi the head to be adjusted angularly with respect to the Saddle.

For effecting longitudinal movement ot the spindle there .is-provided a non-rotary sleeve l2 which surrounds the spindle and is connected for longitudinal movement therewith. This sleeve is "provided with rack teeth lwhich mesh with a pinion let on a horizontal shaft rotatably mounted in the 'rippen-part 0f the head 9. Means ieprovided for rotating the shaft l5, 'this means, as shown, including` a bevel gear 16 on the allait which meshes with a bevel gear 17 on 'an inclined shaft 13. it the lower end ot the shaft 18 are suitable devices whereby the shaft may be turned either .manually orvby' power to effect longitudinal movement of the spindle, For feeding i during' the drilling ill lil@

operation, the power devices preferably thrown into operation. These devices do not of themselves constitute any part of the present invention andi-hey are not therefore shown or described in detail.

For counterbalancingffthe spindle l provide a countervveight 19er 19a which guided for movement along the head parallelly with the spindle l0. rlhis countervveight has secured to it a longitudinal rack 20 or 20a. The countervveight is so shaped and the raclr is so positioned that the central pitch line of the raclr entends through, or approximately tln'cugh, the center ci gravity.

Gearing is interposed between the spindle and the rack ci the counteriveight Whereby the counterweight and the spindle are made to move in opposite directions, tno Weight thus serving to counterbalance the spindle. Preferably use is made in part or the saine gearing 'which serves to move the spindle longitudinally for adjustment or lior feeding. Preferably, a gear 2l is secured to or formed as a part oic the shaft l illustrated in Figs. 3 and l, the gear ai meshes directly with the rack 20. Als illustrated in/lli. 5, a pinion 2l meshes with anidler gear 22, this idler gear meshing in turn with the rack 20. Preferably the pinion 21 is of smaller diameter than the pinion 14e, thus4 causing the countervveight to have a shorter range of movement than the range of movement oi the spindle.

The head 9 is provided with a guide which engages the counterWeight. Preferably this guide is located immediately adjacent the rackand is therefore close to the center of' gravit oi' the counterweightt lis illustrated in Fig. 3, there lis a guide 2S' which projects into a longitudinal groove in the countervveight; rlhe' groove is immediately adjacent the rack 20 so that the body of the rack also engages the guide. fis illustrated in Fig. 5, there is a guide 23, which engages longitudinal surfaces on the countervveight and; on the body of the rack 20a.

' It will be clear that With either construction shovvn the counterweight serves to counterbalance the drill spindle 'for all positions thereof, the line oi movement ciQ the countervveight being always parallel with the line of movement of the spindle. 'llhe counterweight is supported by the pinion 2l or 22 which engages the ack thereof and, inasmuch as the pitch line of the/rack extends through the center of gravity, the counterweight is always supported at its cent/er of gravity. rlhene is therefore little r or no .tendency for the countelrweight to clamp or bind its guide and it therefore moves with a minimum frictional resistance. The possibility 0i clamping or binding is still further reduced by the location of the connected with the spindle and engaging4 guide as near as possible to the rack and thus close to the center of gravity. 4

By comparing lFigsI 3 and 5 it vvillloe seen that in one construction the rack is located at the front of the shaft l5 and in the other construction at the back of the shaiit lijn This change in the location of the rack requires corresponding changes in the shape and position of the countervveight in order that the center of gravity may in both cases be at the pitch line of the rack. Either construction may be used, as recu ed.

llfhat claim is:

l. ln drilling machine, 'the combination with the spindle, of a countervveight movable in parallelism 'to the spindle, a longitudinal rackV secured to the counterweight with its central pitch line extending through the center or gravity thereof, and gearing connected with the spindle and engaging the rack.

2. ln a drilling machine, the combination with thcspindle, of a countervveight movable in parallelism to the spindle, a` longitudinal rack secured to the counterweight with its central pitch line extending through center ci gravity thereof, gearing conud a duide .endaoin the counter- 1 zg tu 5: i, c along lines immediate y ad] acent the .Y machine, the combination .vith 'the spiii of a countervveight Ymovable in parallc. -i tothe spindle, alongi tudinal rack secured tothe countervveight with its central pitch line extending 'through the center of gravity' thereof', gearing connected with the spindle and engaging the rack, and a guide engaging the liody oi' the rack and engaging the countervveio talong lines immediately adjacent the rac n 4. ln a radial drilling machine comprising a vertical column, an armcarried by the column and a longitudinally,movable spindle carried by the arm, the combination with the spindle, of a countervveight movable in parallelism to the spindle, a longitudlnal rack secured to the counter-Weight with its central pitch line extending through the center ci gravity thereof, and gearing thev rack.

5. ln a radial drilling machine com ris-- ing a vertical column, an arm carrie by the column, and a longitudinally movable soindle carried by the arm, the combination with the spindle, of avcountenweight movable in vparallelism to the spindle and partially surrounding it, a longitudinal rack secured to the countervveight with its central pitch line extending through the center of gravity thereof, and gearingconnected with the spindle and engaging the-rac 6. ln a A'radial drilling machinacomnriswith tliespindle and' lengaging the, 

